Treating organic materials using a plasma which is generated by a gas discharge at atmospheric pressure is for example known from U.S. Pat. No. 6,818,102. Here, wooden surfaces are modified by a dielectric barrier discharge. However, no indications of treating biological material containing living cells are given here.
A method of and a device for treating biological material containing living cells using a plasma generated by a gas discharge are known from U.S. Pat. No. 5,866,082 A. Here, a glass bulb filed with neon gas forms a dielectricum. An electrode is arranged on the back of the glass bulb, to which a high alternating voltage generator applies an high alternating voltage to create a gas discharge both in the neon gas within the glass bulb and between the glass bulb and a skin surface. The known method and the known apparatus serve for treating the skin, above which the gas discharge is ignited, with ozone which is formed by a gas discharge in oxygen containing air. The electric power which is supplied by the high alternating voltage generator to the electrode is in the range of several 10 Watt. Thus, it is important, to avoid a direct contact of the skin with the electrode, even if the intermediate glass bulb is destroyed. To this end, a shielding of electrically isolating material protrudes beyond the electrode, which shielding laterally surrounds the glass bulb. Electric energy is supplied to the known apparatus via the usual power network. The known apparatus and the known method are intended for a large area treatment of the skin. The dimensions of the electrode and the glass bulb does not allow for local treatments. Ozone treatment of human skin serves for cosmetic ends in that bacteria at the skin surface are eliminated.
An improvement of the apparatus known from U.S. Pat. No. 5,866,082 A is described in GB 2,378,387 A. This improvement shall solve the problem which is connected with a possible break of the glass bulb. To this end, a protection coating is provided to the glass bulb, which protection coating comprises openings to enable the gas discharge between the glass bulb and the skin surface. It can be taken from GB 2,378,287 A that the glass bulb is no longer able to conduct electrical energy for the gas discharge as soon as it breaks and the neon gas disappears.
An electro surgical instrument is known from DE 198 20 240 A1, which instrument forms a plasma by means of a barrier free gas discharge within an inert gas or gas mixture comprising no oxygen. The main effect of the plasma on the tissue treated with this instrument is thermal; i.e. a thermal coagulation takes place. A barrier-free electric discharge can only be realized within a very high frequency range and with comparatively high electric power.
In the field of deontology the treatment of dental caries with ozone is known. To this end, a limited area above that site of a dent which has caries is purged with ozone. The ozone is generated in a stationary apparatus and supplied via a tube to a small treating dome arranged at an oral probe. The ozone is sucked off from the treating dome again, and unused ozone is neutralized in a filter. Overall, the known apparatus for caries treatment is quite complicated.
Thus, there is a need for a method of and an apparatus for treating biological material containing living cells using a plasma generated by a gas discharge with little energy consumption, with little danger of accident and also in small spatially limited areas.